As Temperatures Warm, Watch For Algae Blooms

Washington health and environmental officials are urging people to be on the lookout for harmful algal blooms as temperatures start to warm. While many types of algae are beneficial, some blue-green algae can produce toxins that make people and animals sick.

This year, experts say drought conditions, low snowpack, and warmer, shallower lakes and rivers could increase the risk of toxic blooms across the state. Health officials warn that harmful algae aren't always easy to spot. Watch for water that looks like green paint, pea soup, foam, scum, or thick floating mats. Even clear water can contain toxic algae growing below the surface.

What Causes Blooms?

Human sources of excess nutrients — especially phosphorous — are one of the biggest contributors to algae blooms. These nutrients often enter lakes and rivers through common sources such as:

Fertlizer runoff
Failing septic systems
Stormwater runoff from urban or industrial areas

Even when nutrient levels are stable, unpredictable weather conditions or changes in water flow can trigger blooms. For example, a lake with normal nutrient levels in spring might still experience a bloom in summer due to a storm or urban runoff. Similarly, a lake with high levels of nutrients can avoid a bloom if certain weather conditions are not met.

Photo: Washington State Department of Ecology

What can you do to prevent harmful algal blooms?

While harmful algal blooms are hard to predict, there are steps you can take to reduce a lake’s chance of developing a bloom.

Clean up pet waste
Choose phosphate-free detergents and soaps
Don’t over-water lawns and gardens
Maintain your septic system to prevent leaks
Don't feed waterfowl, like ducks and geese
Reduce or eliminate the use of fertilizers
Wash vehicles at a commercial car wash or away from storm drains
Maintain native vegetation around the lake.

Though predicting harmful algal blooms is difficult, we all play a role in prevention and safety. With awareness and responsible practices, we can help protect Washington’s waters for everyone to enjoy.

Heath Concerns

People and animals exposed to contaminated water may develop skin rashes, vomiting, diarrhea, or other unexplained illnesses.

Owners are encouraged to keep animals away from suspicious water and seek veterinary care if symptoms develop. Officials say the safest approach is to avoid water with visible algae and obey all posted warnings and closures.

If exposure occurs, rinse immediately with clean water and seek medical attention if needed.

If you have a story idea for the PNW Ag Network, call (509) 547-9791, or e-mail glenn.vaagen@townsquaremedia.com